# Faculty News Briefs

### March 2016

On March 8, 2016 Visiting Assistant Professor Stathis Charalampidis gave an invited talk at Bowdoin College in Brunswick, ME with the title “Dark-Bright Solitons and Their Two-Dimensional Counterparts in Coupled Nonlinear Schrödinger (NLS) Systems”.

During February and March 2016 Professor Krista J Gile gave departmental seminars at the University of Wisconsin in Madison (February 17), Yale University (March 1), and McGill University (March 15). She also gave a slam talk and poster at the UMass Computational Social Science Institute CSS and Health Mixer on March 25.

During March 2016 Professor Nestor Guillen visited the University of Wisconsin and Michigan State University, both to conduct research and to speak in the Geometric PDE Seminar (Wisconsin) and the Analysis and PDE seminar (MSU). At both universities he gave a talk titled “Min-Max Formulas for Integro-Differential Equations and Applications”.

On March 12, 2016 Visiting Assistant Professor Robin Koytcheff gave a talk titled “Homotopy String Links, Configuration Spaces, and the Kappa Invariant” at the 50th Spring Topology and Dynamics Conference at Baylor University in Waco, TX.

On March 3, 2016 Professor Michael Lavine delivered the talk titled “WHIM: Function Approximation Where It Matters” at North Carolina State University.

Professor Yao Li gave the following talks during February and March 2016: (1) “Systematic Seasures of ODE-Modeled Complex Networks”, MBI Emphasis Workshop: Interplay of Stochastic and Deterministic Dynamics in Networks, Ohio State University, February 23 (invited talk); (2) “Nonequilibrium Steady-States for Some Interacting Particle Systems”, Probability Seminar, Brown University, March 15 (invited talk); (3) “Polynomial Convergence to Nonequilibrium Steady-States”, Seminar on Stochastic Processes 2016, University of Maryland, March 18 (short talk). The following paper co-written by Yao was also published: "Local Thermal Equilibrium for Certain Stochastic Models of Heat Transport" (with Peter Nandori and Lai-Sang Young), Journal of Statistical Physics, April 2016, Volume 163, Issue 1, pages 61-91.

On March 17, 2016 Professor Jenia Tevelev delivered a talk titled “The Craighero-Gattazzo Surface is Simply-Connected” in the Séminaire de géométrie algébrique de Jussieu in Paris <https://www.imj-prg.fr/tga/sem-ga/archives.html>.

During the period March 14-20, 2016 Visiting Assistant Professor Yaping Yang visited the Perimeter Institute forTheoretical Physics in Waterloo, Canada.

During the period February 28 - April 30, 2016 Professor HongKun Zhang was a Visiting Professor at Warshington University in St. Louis. She gave an invited talk titled “Diffusion Billiard Models” in the Geometry Seminar.

On March 3, 2016 Visiting Assistant Professor Gufang Zhao visited the State University of New York in Albany, where he gave a talk in the Algebra and Topology Seminar titled “Quiver Varieties and Elliptic Quantum Groups.” During the period March 14-20, 2016, Visiting Assistant Professor Gufang Zhao visited the Perimeter Institute for Theoretical Physics in Waterloo, Canada. On March 17 he gave a 90-minute talk in the Mathematical Physics Seminar titled “Quiver Varieties and Elliptic Quantum Groups”.

### February 2016

On February 17, 2016 Professor Tom Braden gave a talk in the Stony Brook University Algebraic Geometry Seminar titled “Modular Representation Theory, Springer’s Resolution and Hypertoric Varieties.”

Professor Matthew Dobson presented a poster titled “Algorithms for the Long-time Simulation of Steady Nonequilibrium Flow” at the COSMOS workshop in Paris. The workshop took place February 2-5, 2016.

On February 24, 2016 Professor Patrick Flaherty published a paper titled “GEMINI: a computationally-efficient search engine for large gene expression datasets” in *BMC Bioinformatics* with Hachem Saddiki, a graduate student at UMass Amherst, and Timothy DeFreitas, an undergraduate student at WPI, now at the Broad Institute. The article is open-access and available at http://bmcbioinformatics.biomedcentral.com/articles/10.1186/s12859-016-0....

Between February 5 and February 7, 2016 graduate students in the department, including Emma Kearney, a MSc student in statistics, and Ankita Shankhdhar, a MSc student in applied mathematics, assisted in organizing an interdisciplinary event with the goal of using ideas from mathematics, statistics, and computation to analyze a dataset provided by the Pioneer Valley Transit Authority (PVTA). More than eighty graduate students from all over campus participated in the event. The event was organized by the “Graduate Researchers interested in Data” (GRiD) group.

On January 26, 2016 Professor Rob Kusner led a group of about sixty U. C. Berkeley Math Circle students, whose ages ranged from 7 to 17, in a two-hour investigation of link topology and the geometry of equilibrium configurations of electrons on the sphere. One of the most crowd-pleasing activities was when trios of students linked arms to make Borromean Rings and other 3-component links! (Where is our Five Colleges Math Circle?!) Rob also lectured on “Soap Bubbles, Spherical Metrics and Quadratic Differentials” in the February 16 Riemannian Geometry Seminar at MSRI.

Professor Michael Lavine attended and made brief presentations at the SAMSI Workshop on Optical Imaging Data Analysis, February 1–2, 2016.

Professor Ivan Mirkovic attended the Conference on Geometric Representation Theory, which took place at the Simons Center at Stony Brook University during the period January 4–29, 2016. He gave a 90-minute talk on “Loop Grassmannians, Classifying Spaces and Local Spaces.”

Professor Franz Pedit gave three invited talks at the OCAMI-KOBE-WASEDA Joint International Workshop on Differential Geometry and Integrable Systems sponsored by the International Research Network Project “SYMMETRY, TOPOLOGY and MODULI.” The dates in February 2016, the locations in Japan, and the titles of the talks are as follows: (1) February 13, Osaka, “Harmonic Maps and the Self Duality Equations”; (2) February 14, Osaka, “Hilbert’s 21st problem for Loop Groups with Applications to Surface Geometry”; (3) February 18, Tokyo, “Constrained Willmore Surfaces and Conformal Willmore Gradient Flow.”

During the period February 7–12, 2016 Visiting Assistant Professor Yaping Yang attended the Workshop on Vertex Algebras and Quantum Groups, which was held at the Banff International Research Station. She gave a talk titled “Cohomological Hall Algebras and Affine Quantum Groups.” Details about the conference are available at http://www.birs.ca/events/2016/5-day-workshops/16w5070.

### January 2016

During the last week in January 2016 Professor Tom Braden visited Louisiana State University and gave two talks, an undergraduate colloquium titled “Geometry of Machines” and a graduate colloquium titled “Deformations in Topology and Algebra.”

On January 15, 2016 Visiting Assistant Professor Robin Koytcheff gave a talk in the University of Victoria Topology Seminar titled “Homotopy String Links, Configuration Spaces, and the Kappa Invariant.”

On January 21, 2016 Professor Michael Lavine delivered a talk titled “WHIM: Function Approximation WHere It Matters” at Penn State.

During the January break Professor Eric Sommers attended the Taipei Conference in Representation Theory V at the Institute of Mathematics at the Academia Sinica in Taipei, Taiwan, where he gave a one-hour talk on “A Family of Weyl Group Representations.” The conference was held in honor of George Lusztig's upcoming 70th birthday. At the start of the conference, former AMS President David Vogan awarded the inaugural AMS Chevalley Prize in Lie Theory to Geordie Williamson, who then gave the opening lecture of the conference. The Chevalley Prize was established in 2014 by George Lusztig to honor Claude Chevalley (1909-1984).

During January 2016 Professor Jenia Tevelev was a visiting professor at La Pontificia Universidad Católica de Chile in Santiago, Chile. While there, he visited Professor Giancarlo Urzua, a former VAP at UMass Amherst. He also delivered a survey talk titled “Derived Category of Moduli of Pointed Rational Curves” at the CIMPA-ICTP Research School on “Toric Methods in Geometry, Arithmetics, and Dynamics.”

### December 2015

During the period December 1-4, 2015 Professor Markos Katsoulakis co-organized the workshop Predictive Multiscale Materials Modeling at the Turing Gateway to Mathematics, which is part of the Isaac Newton Institute in Cambridge, UK. The link to the workshop is http://www.turing-gateway.cam.ac.uk/uqm_dec2015.shtml. The focus of the workshop was on fundamental mathematical, statistical, and machine-learning approaches to impact data-driven predictive multiscale materials modelling and design. One of the primary aims was the identification and integration of synergistic methodologies from different research fields, including applied mathematics, data science, materials, physics and chemistry, uncertainty quantification and machine learning. Considering the recent significant advances in materials characterization techniques, the workshop emphasized (a) mathematical and statistical developments for a data-driven approach to predictive materials modeling and (b) accelerated design of materials and processes in the presence of inherent, structure, process, model and epistemic (e.g. limited data) uncertainties. In addition to leading academics, representatives from industry (Rolls-Royce, Airbus, Dassault Systèms, Schlumberger, and others) participated in panel discussions on industrial challenges for predictive materials modeling as well as for integrating and transferring advances in the area taken place in academic institutions to industrial practices. The video and lecture presentations from the workshop are available on the Turing Gateway to Mathematics website at the Isaac Newton Institute for Mathematical Sciences at the University of Cambridge (http://www.turing-gateway.cam.ac.uk/uqm_dec2015-programme.shtml).

The Association of Members of the Institute for Advanced Study has elected to its Board of Trustees the following two people: Rob Kusner, Member (1992–93, 1997) and Visitor (1996) in the School of Mathematics, and William E. Connolly, Member (1986–87) in the School of Social Science.

On December 2, 2015 Professor Michael Lavine gave the talk titled "WHIM: Function Approximation Where It Matters" at SAMSI.

During the period December 14-18, 2015 Professor Ivan Mirkovic was a Visiting Professor at the University of Queensland in Brisbane, Australia. He gave an invited talk at a conference on representation theory.

During the period December 15, 2015 – January 7, 2016 Professor Franz Pedit gave a lecture series consisting of 6 two-hour lectures titled "Harmonic Maps from Riemann Surfaces" in the Peking University Distinguished Scholar Programme. In addition he gave two colloquia. The first, titled "Hilbert's 21st Problem for Loop Groups and Constant Mean Curvature Surfaces," was held at Peking University on December 25, and the second, titled "Conformal Willmore Flow," was held at Tsinghua University on December 30.

On December 2, 2015 Jenia Tevelev delivered a talk titled "Craighero-Gattazzo Surface Is Simply-Connected" at the Algebraic Geometry Seminar at the University of Georgia at Athens.

### November 2015

Just before Thanksgiving, Professor Rob Kusner managed to stuff his schedule with a short course at Brown University, beginning with a Friday, November 20 colloquium talk on “The Moduli Space of Complete Soap Bubbles,” which preceded a pair of two-hour seminars on “the leftovers” the following Monday and Tuesday. Earlier in the month, on Thursday, November 5, Rob had given a preliminary version of the colloquium talk at University of Pennsylvania, where he’s on sabbatical this fall.

Both Professor Bruce Turkington and his Postdoctoral Associate, Simon Thalabard, presented short talks at the 68th Annual Meeting of the Division of Fluid Dynamics, American Physical Society, held in Boston during the period November 22–24, 2015. They spoke about their “optimal closure” approach to turbulence modeling. On November 17, Simon Thalabard visited Brown University in Providence, where he gave a talk on the same topic at the weekly fluid seminar in the Department of Physics.